I am right at 200 rounds. I had some feed issues (which I recorded during the first 20 rounds). It had FTF/FTE every shot (with two bullets falling out of the chamber when I removed the mags). Then boom, everything started running perfectly over the next 180 rounds. Maybe century isn't joking about the break-in. The gun is a joy to shoot and practically identical to my SP5 except the bolt looks a little rougher (casting?) in the AP5. I am going to do a little 500 round break-in video and put it up next week with pictures of the internals for comparison. Let me know if you want to see anything specific. I am running it with an Omega 9k.